The present invention relates to mobile communications, and particularly to mobile terminal power management.
Emerging communication technologies such as E-UTRA (Evolved Universal Terrestrial Radio Access) or UTRA (Universal Terrestrial Radio Access) are designed to support mobile communications upon the basis of mobile user equipment (UE), e.g. mobile terminals or handset devices. In this regard, the development of UE devices such as mobile terminals or hand sets for communicating over radio communication networks is subject to improvements reflecting certain technology trends. One technology trend is to reduce weight and size of the UE which results in a need for smaller energy sources, e.g. batteries. Another technology trend is to provide more and smarter functions within the UE which is often associated with an increased consumption of electrical power. Even though the energy source development has brought increasingly powerful batteries, the UE power consumption is a critical parameter especially with regard to high data rate UEs which, by way of example, are suitable for WCDMA (Wide Band Code Division Multiple Access) and E-UTRA radio access networks. The energy consumption is further affected by thermal energy dissipation may be an important aspect with respect to power consumption in future UE technologies.
In the following, by way of example and without limiting the invention, technological background, problems and solutions with respect to power consumption are described by focusing on the LTE technology.
Initiated in recent years, the LTE project focuses on enhancing the Universal Terrestrial Radio Access (UTRA) and optimizing 3GPP's radio access architecture. Targets have been set providing an average user throughput of three- to four-times the Release 6 HSPA (High Speed Packet Access) levels in the Downlink-HSDPA-(100 Mbps), and two to three times the HSPA levels in the Uplink-HSUPA-(50 Mbps). Orthogonal Frequency Division Multiplexing (OFDM) has been selected for the Downlink and Single Carrier-Frequency Division Multiple Access (SC-FDMA) for the Uplink. The Downlink will support data modulation schemes QPSK, 16QAM, and 64QAM and the Uplink will support BPSK, QPSK, 8PSK and 16QAM. LTE's E-UTRA is designed to be flexible using a number of defined channel bandwidths between 1.25 and 20 MHz (in contrast to the UTRA's fixed 5 MHz channels).
The uplink (UL) transmission of the LTE system is usually performed with a 1 ms granularity, i.e. the UL transmission time interval (TTI) for LTE is 1 ms. The UE receives the information in frame x about the amount of data to be send in frame x+4. Before the actual transmission the UE creates the uplink data blocks and sends them out at frame x+4 with the indicated transmission power.
In order to implement UE devices employing the LTE technology, a mobile platform architecture enabling an integration of the LTE technology into future mobile phones, data cards and other devices requiring wireless connectivity based on high data rates like e.g. cameras, PDAs (Personal Digital System), TVs (Television) etc. may be chosen. In this regard, the power consumption of corresponding UEs may be subject to certain power consumption limits and restrictions which are, by way of example, summarized in the following table for a UE being implemented into a PCIe (Peripheral Component Interconnect Express) mini card.
PCIe Mini CardNotes3.3 V Tolerance±0.3V3.3 V Average Current1100mAAveraged over any 1second interval3.3 V Maximum Current2750mAAveraged over 100 μSecfor PCIe.1.5 V Tolerance±0.075V1.5 V Average Current375mA1.5 V Max Current500mAAllowed total heat2.3WWhen all componentsdissipation for class 1are rated for a casedevicestemperature of 90 C.Allowed total heat3.1Wdissipation for class 2devices
For a deployment in a USB dongle/stick the 5V (Tolerance: ±0.25V) Average and Maximum Current per USB port is 500 mA. There is no restriction concerning the allowed heat dissipation. I.e. in case a USB dongle has 1 USB port it can consume maximum 2.5 W, in case it has 2 USB ports it can consume up to 5W. The above listed values can be taken as limits for a mobile phone platform when deployed in a single-mode device. In case of a deployment in a multi-mode device the power consumption of other devices has to be taken in account, which leads to a further reduction of the maximum allowed limits.
In this regard, the U.S. Pat. No. 6,760,311 discloses a mobile terminal, wherein certain operating parameters, such as the transmission data rate, are controlled such that a certain temperature threshold is not exceeded. The U.S. Pat. No. 6,064,857 discloses a satellite telephone with hybrid battery and capacitor power supply comprising a switching circuit coupled to said battery and said capacitor for selectively coupling one of (a) the battery alone, (b) the capacitor alone, and (c) both together in parallel to the transmitter, depending on the data rate.